This is actually an interesting topic! I understand that you would want to give the Scriviner an official name, but not giving him one, just like the Elder and the Housekeeper, is an homage to older Monster Hunter game rules where a lot of characters are just labeled and defined, rather than named. It's only recently in Monster Hunter Rise where characters are actually named. This is the reason why the Scriviner does not canonically have a name.
But I was thinking David at one point....
- Roda -